Techniques
Sample rules
Windows Unusual Count Of Users Failed To Authenticate From Process
- source: splunk
- technicques:
- T1110.003
- T1110
Description
The following analytic identifies a source process failing to authenticate multiple users, potentially indicating a Password Spraying attack. It leverages Windows Event 4625, which logs failed logon attempts, and uses statistical analysis to detect anomalies. This activity is significant as it may represent an adversary attempting to gain initial access or elevate privileges within an Active Directory environment. If confirmed malicious, the attacker could compromise multiple accounts, leading to unauthorized access, data exfiltration, or further lateral movement within the network.
Detection logic
`wineventlog_security` EventCode=4625 Logon_Type=2 ProcessName!="-"
| bucket span=2m _time
| stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as user by _time, ProcessName, SubjectUserName, Computer
| eventstats avg(unique_accounts) as comp_avg , stdev(unique_accounts) as comp_std by ProcessName, SubjectUserName, Computer
| eval upperBound=(comp_avg+comp_std*3)
| eval isOutlier=if(unique_accounts > 10 and unique_accounts >= upperBound, 1, 0)
| search isOutlier=1
| `windows_unusual_count_of_users_failed_to_authenticate_from_process_filter`
Windows Multiple Users Failed To Authenticate From Process
- source: splunk
- technicques:
- T1110.003
- T1110
Description
The following analytic detects a source process failing to authenticate with 30 unique users, indicating a potential Password Spraying attack. It leverages Windows Event 4625 with Logon Type 2, collected from domain controllers, member servers, and workstations. This activity is significant as it may represent an adversary attempting to gain initial access or elevate privileges within an Active Directory environment. If confirmed malicious, this could lead to unauthorized access, privilege escalation, or further compromise of the network, posing a severe security risk.
Detection logic
`wineventlog_security` EventCode=4625 Logon_Type=2 ProcessName!="-"
| bucket span=5m _time
| stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as tried_accounts by _time, ProcessName, SubjectUserName, Computer
| rename Computer as dest
| where unique_accounts > 30
| `windows_multiple_users_failed_to_authenticate_from_process_filter`